My invention relates in general to flight controlling devices for aircraft. More specifically, my disclosure presents a system for aft fuselage flight controls, on forward lifting elevator aircraft.
Most aircraft in use are designed with the main wing surfaces forward of the rearwardly placed tail surfaces. Takeoff and landing requires negative tail lifting, which adds to the main forward wing loading, at a time when this condition is least desirable. Most conventional aircraft also have very complex leading edge slats on the main wing surfaces. These leading edge slats are costly to manufacture and are also heavy items.
My studies show that the forward lifting and flight controlling aircraft, do not have any great advantage over conventional aircraft, until the aircraft is in the 50-60 seat (passenger) category, and larger. In this category, the main aft wing can be brought forward from the end of the aircraft fuselage, and by doing so, balance the aircraft, by placing engines, supported by pods, on the aft fuselage. This advantage is such that trailing edge flaps can be used on the main aft wing.
A number of designs have suggested airbrakes for aircraft. Examples include U.S. Pat No. 1,413,086, titled Brake for Aircraft; U.S. Pat. No. 2,698,149, titled Aircraft Speed Retarding Device; U.S. Pat. No. 2,421,870, titled Air Brake for Aircraft; U.S. Pat. No. 2,444,291, titled Airplane Air Brake; U.S. Pat. No. 3,128,068 titled Petal Type Door For Cargo Aircraft; U.S. Pat. No. 2,525,844, titled Parachute for Aerodynamic Braking of Airplanes; U.S. Pat. No. 2,773,659, titled Full Powered Human Pilot-Autopilot Airplane Control System; U.S. Pat. No. 4,003,533, titled Combination Airbrake and Pitch Control Device; and U.S. Pat. No. 2,942,813 titled Combined Speed Brake, Escape Hatch and Baggage Access Door for Aircraft. The Speed Brake and Air Brake configurations include vertical and horizontal panels as well as air pockets and parachutes, with Speed Brake and Air Brake locations varying from the main wing to the aft end of the fuselage. A number of commercial aircraft in the past have used a split airbrake, with the hinges in the vertical or near vertical position, at the extreme end of the aircraft fuselage. The airbrake is opened on each side of the fuselage centerline, to generate drag as the aircraft moves in its directed flight path, to slow the aircraft down in flight, and, particularly, to slow down the aircraft pending a landing. However, these designs do not teach vertical panels to control a tail down movement. Some designs suggest flight controls to overcome forward lifting elevator aircraft flight control difficulty. Examples include U.S. Pat No. 2,363,550, titled Differentially Controlled Surfaces For Lateral and Directional Control; and U.S. Pat. No. 2,430,793, titled Aircraft Elevator Construction. However, these designs do not teach vertical panels to control a tail down movement for forward lifting elevator aircraft. It is significant, however, that none of the prior art patents identified above are concerned with the specific problems solved by applicant. Nor do they disclose devices, which would satisfactorily solve those problems.
A need exists in the art to counter a nose down pitching condition when main aft wing flaps are deployed to slow the aircraft down prior to landing on forward lifting elevator aircraft. Therefore, it would be desirable to provide a flight control system on forward lifting elevator aircraft having a means to counter a nose down pitching condition when main aft wing flaps are deployed to slow the aircraft down prior to landing.
It is a primary object of the my invention to provide a flight control system on forward lifting elevator aircraft having a means to counter a nose down pitching condition when main aft wing flaps are deployed to slow the aircraft down prior to landing.
My invention, in one embodiment, comprises an aft fuselage flight control system, for flight control of a forward lifting elevator aircraft. The aft fuselage flight control system attachment with the aft end of a fuselage of a forward lifting elevator aircraft, the aft fuselage flight control system comprising at least two aft vertical flaps with each aft vertical flap including a forward edge, and an aft trailing edge; a means for hingedly connecting the forward edge of each of the aft vertical flaps with the aft end of the fuselage of an aircraft such that in the direction of the rear of the aircraft, the forward edge forms an acute angle with the aircraft centerline, and such that the aft vertical flap may move out beyond an aircraft boundary layer; and an aft end of a fuselage connected with each of the means for hinging connected with the forward edge of the aft vertical flap at an angle between horizontal and vertical; and a means for spreading connected with each vertical flap and with the aft end of the fuselage such that the means for spreading can spread the flaps symmetrically and in an upward and outward motion with respect to the aircraft centerline.
Another embodiment of my invention further comprises an aft fuselage flight control system wherein the means for hingedly connecting the forward edge of each of the aft vertical flaps with the aft end of the fuselage includes a hinge axis defined by the centerline of the means for hingedly connecting, and wherein the means for spreading the aft trailing edge of the aft vertical flap further comprises; an actuating unit connected with the aft end of the fuselage of an aircraft on an aircraft fuselage centerline and at approximately a right angle with respect to the hinge axis; a piston rod moving out from the actuating unit; a piston rod attachment connected with the piston rod; a piston rod guide, located along the aircraft fuselage centerline, connected with the piston rod attachment to guide the piston rod in a straight line motion to ensure symmetrical opening on each side of the aircraft centerline when activated; a push rod connected with the piston rod attachment for each of the aft vertical flaps; a radius bracket with a lower radius arm connected with the push rod for each of the aft vertical flaps; a centerline hinge bearing connected with the aft end of the aircraft fuselage securing the radius bracket allowing the radius bracket to oscillate about it""s hinged axis; two upper radius arm connected with the radius bracket; a control rod connected to each upper radius arm; and a flap bracket connected between each control rod and the aft vertical flap.